MX1 and viral infectious disease: The blood MxA levels (median [IQR]) were higher in children with a viral infection (467 [235 to 812] μg/L) compared to children with bacterial infection (119 [68 to 227] μg/L, P < 0.001) or children with a bacterial infection and coincidental virus finding (150 [101 to 212] μg/L, P < 0.001) (Fig. 2).